Wishniak is a black cherry soda that is named after real wishniak, which is actually an Eastern European vodka-based black cherry liqueur. (If you like reading about liquor, check out my other site here.) Legend has it that this genre of soda was conceived and named in the Eastern European disaporae of Philadelphia. A brand called Frank's was probably the original version, and it call still be bought today.
Some of the larger soft drink companies have issued their own versions of Wishniak, and Canada Dry is among them, which denotes it as a limited availablity(specifically, probably regional) varietal.
Full disclosure: I'm not a big fan of black cherry flavored foods. I find that I prefer sweeter cherry flavors like found in Coca-Cola Cherry or Cheerwine.
The flavor of this stuff is pretty good. It's a tad more bitter and sour than more traditional cherry sodas, but it maintains a sweetness that keeps it more on the crowd-pleaser side. This may be a bit tame for true black cherry enthusiasts. The flavor is indeed "dark" with a character that will remind you of other dark berries, such as raspberry or grape. There's also a bit of black pepper that bites you near the end. On the swallow, this soda manages to leave a short crisp finish with almost no aftertaste.
Canada Dry Black Cherry Wishniak: (Good)
Acquired: privately-owned convenience store